Add the ability to save to PTW, and essentially stay in PTW mode, when editing a .bic/.bix file. Essentially, this will give an option to either convert to Conquests, or stay in PTW, and Conquests-specific options will be disabled.

A "fallback" option allowing to save PTW-compatible scenarios from Conquests ones would be an interesting second version of this, but is not within the scope for this item.